What with them jackhammering up my bathroom to repair an 80 year old steam pipe encased in 12 inches of concrete, I'm in a construction-tool gadget mood.
I want to post about the greatest tool since sliced bread, the
oscillating "multi" tool.
There are a bunch of different models of these, from cheap $30 corded versions (that work fine) to $200 cordless versions (i always prefer cordless).
Basically they just vibrate at high speeds and can accept different saw-like heads. They are very similar in spirit to the ubiquitous dremel (
rotary tool), in that there a million different little tasks that they can make quick work of.
Note: A Dremel is as essential, if not more so, than an oscillating tool -- so start with one of those if you don't own one already.What makes these oscillating multi tools so useful is that they like you use a very thin blade flush with an object and with excellent precision. For example if you strip a screw you could use it to cut the screw off half way -- or you could use it to slip behind some woodworking trim to cut it loose, etc.
Anyway, I consider it an essential gadget for serious DIY home-construction type folks.

BONUS "gadget":
This may be one of the cheapest non-gadget DIY gadgets I can recommend, but also one of my favorites:
A box of disposable latex gloves:

I always have a couple of boxes of these on hand.. You'd be surprised how handy they are to have around and make a million little tasks less onerous.